Oklahoma lost its coach on Sunday when Lincoln Riley announced that he is taking the USC job, and now it's lost its opening day starting quarterback and former Heisman favorite. Redshirt sophomore Spencer Rattler announced Monday on Twitter that he has entered the transfer portal. 

"Sooner Nation, thank you for allowing me to be a student-athlete at this prestigious institution," he wrote. "Thank you to every teammate and coach these last three seasons. We won several games together and made memories that I will cherish forever. Special thanks to my family and friends for your support. Thank God for the game of football. It's the ultimate team sport and brings people and communities together unlike anything else. At this time, I would like to announce that I have decided to enter the transfer portal to continue my academic and athletic career. Thank you again, Oklahoma. I will miss you.

Rattler threw for 4,595 yards, 40 touchdowns and 12 interceptions in three seasons in Norman. He entered the 2021 season as the favorite to win the Heisman Trophy after throwing for 3,031 yards and 28 touchdowns in 2020 -- his first season as the Sooners' starting quarterback. 

He started the first six games of the season before being benched vs. Texas after poor play. Caleb Williams took over and started the remaining six games under center. 

Rattler was a five-star prospect and the No. 11 overall player in the Class of 2019 out of Pinnacle High School in Phoenix, Arizona. He was named the MVP of the prestigious Elite 11 camp prior to his senior year of high school.

Where could Rattler land? Let's examine some potential destinations

Ole Miss

The Rebels are losing Heisman contender Matt Corral to the NFL Draft, which has left a big vacancy on the roster. Coach Lane Kiffin and offensive coordinator Jeff Lebby have established themselves as two of the top offensive minds in the country and any quarterback in his right mind would jump at the chance to play for either of them.

Corral's primary backup this season was Luke Altmyer, but the former four-star prospect only attempted nine passes in mop-up duty. Rising senior John Rhys Plumlee led the SEC in rushing at 113.67 yards per game as a dual-threat quarterback in 2019 under coach Matt Luke, but has been playing wide receiver for Kiffin over the last two seasons. Plus, he is a highly-regarded baseball prospect, so it's unlikely that he'll play football after this season's Major League Baseball Draft. 

South Carolina

The Gamecocks are coached by Shane Beamer, who was on the Sooners staff from 2018-20. That overlaps with Rattler's first two seasons in the program. Beamer, who posted a surprising 6-6 season in Year 1 despite never having served as a head coach in college before, is also in the market for a new quarterback.

Luke Doty was injured all year, Zeb Noland -- a graduate assistant with the program before Doty's injury -- will actually become a graduate assistant next season and St. Francis transfer Jason Brown threw eight touchdowns and six interceptions in seven games, the last four of which were as the starter. 

Beamer is familiar with Rattler's skill set and can provide a nice landing spot for Rattler to prove himself to NFL scouts. 

SMU

The Mustangs just hired Rhett Lashlee, who did great work as Miami's offensive coordinator with Tyler Van Dyke this year and D'Eriq King in 2020. Lashlee is widely regarded as one of the top up-and-coming offensive minds in the industry, and SMU could lose rising senior Tanner Mordecai to the NFL Draft after this season.

Lashlee utilizes an up-tempo attack that, at times, has benefitted from a dual-threat quarterback. Rattler isn't a weapon on the ground like King, but is more than just a willing runner and can sling it all over the field. He's a good fit for a coach and system that can maximize his skill set. 

Arizona

Rattler is from Phoenix and his home-state Wildcats are nothing short of a disaster. They went 1-11 this season and the only player who threw more touchdowns than interceptions was wide receiver Jamarye Joiner, who completed just 4-of-10 passes for 89 yards, two touchdowns and no interceptions. 

Jedd Fisch could be on the hot seat in 2022 and it's not like he has any other hot quarterback prospects on the horizon. Rattler not only could revitalize a program in his own state, but could do it for a team that desperately needs a boost.